Aqueous creams of organosilicon compounds

ABSTRACT

The invention relates to a stable aqueous cream consisting of the following components: (A), which is selected from (A1) C 1 -C 20 -alkyl-C 2 -C 6 -alkoxysilanes and (A2) organopolysiloxane containing alkoxy groups; (C) an emulsifier; and (D) an organic solvent. The stable aqueous cream is suitable for the hydrophobic impregnation or priming of mineral building materials.

The invention relates to an aqueous firm cream and a process forimpregnating or priming mineral building materials to impactwater-repellency.

Organosilicon compounds are used in building protection especially owingto their outstanding impregnation effect for protection from water anddirt. Siliconates, silicone resins, monomeric silanes and oligomericsilanes have been established for years for this application. The activeingredients are usually dissolved or dispersed in low-viscosity carriermedia, such as, for example, organic solvents or water. Low-viscosityactive ingredients, such as, for example, monomeric silanes orlow-viscosity mixtures of silanes and siloxanes, can also be appliedundiluted to the building material.

A disadvantage of these impregnating compositions is that they readilyrun off or drip off vertical surfaces and very particularly duringoverhead work.

Silane-, siloxane- or silicone resin-based compositions containingmineral thickeners can on the other hand also be applied as a relativelythick layer to the building materials, without running off. Theorganosilicon compound penetrates into the building material and thethickener remains behind. U.S. Pat. No. 4,076,868 describes, forexample, solutions of methylpolysiloxane in toluene which are thickenedwith silica. WO 95/25706 describes a process for impartingwater-repellency with solvent-free silane/siloxane mixtures thickenedwith bentonites. The disadvantage of these processes is that the mineralthickener remains behind on the building material and has to be removedand disposed of.

In EP-A-819 665, these disadvantages are counteracted by using so-calledwater-repellent creams. These are aqueous, firm products based onorganosilicon compounds, which are free of solids and organic solvents.The active ingredient content of these creams is preferably 60 to 95%.

On absorptive building materials, such as, for example, bricks,concrete, sand-lime bricks, fibre cement boards, mineral renders andmany natural stones, impregnating compositions whose active ingredientcontent is frequently in the range of 5-25% are generally applied. Forthese applications, the active ingredient concentration of thewater-repellent creams described in EP-A-819 665 is too high.

It was the object of the present invention to provide water-repellentcreams whose application includes all advantages of the water-repellentcreams of EP-A819 665 but whose active ingredient content canadditionally be adjusted as desired.

The invention relates to an aqueous, firm cream which contains thecomponents

(A) which are selected from

(A1) C₁-C₂₀-alkyl-C₂-C₆-alkoxysilanes and

(A2) organopolysiloxane containing alkoxy groups,

(C) emulsifier and

(D) organic solvent.

In a preferred embodiment, the aqueous cream additionally contains acomponent (B) which contains aminoalkyl groups and is selected fromalkoxysilane (B1) containing aminoalkyl groups or organopolysiloxane(B2) which, in addition to other organosiloxane units, contains thosesiloxane units which have radicals bonded via SiC and having basicnitrogen, with the proviso that the amine number of theorganopolysiloxane (B2) is at least 0.01.

Pasty, water-containing formulations which are emulsion systemscomprising water-immiscible oil phase, namely active ingredients (A) andoptionally (B) plus organic solvents (D), water and emulsifiers (C), aredesignated as cream. The cream is considered to be firm if it can beapplied by means of a doctor blade or brush or by spraying in a coatthickness of at least 0.5 mm to vertical absorptive mineral buildingmaterials, such as, for example, sand-lime brick or clay brick, and,after application, does not run down more than 1 cm before it has beencompletely absorbed by the building material.

Preferably, the C₁-C₂₀-alkyl-C₂-C₆-alkoxysilanes (A1) have 1 or 2identical or different, optionally halogen-substituted monovalentC₁-C₂₀-alkyl radicals bonded via SiC, and the remaining radicals areidentical or different C₂-C₆-alkoxy radicals. Methoxysilanes undergohydrolysis too rapidly and prevent a sufficient shelf life.

Examples of the C₁-C₂₀-alkyl radicals are methyl, ethyl, n-propyl,isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyland tert-pentyl radicals; hexyl radicals, such as the n-hexyl radical;heptyl radicals, such as the n-heptyl radical; octyl radicals, such asthe n-octyl radical, and isooctyl radicals, such as the2,2,4-trimethylpentyl radical; nonyl radicals, such as the n-nonylradical; decyl radicals, such as the n-decyl radical and dodecylradicals, such as the n-dodecyl radical; cycloalkyl radicals, such ascyclopentyl, cyclohexyl, 4-ethylcyclohexyl and cycloheptyl radicals,norbornyl radicals and methylcyclohexyl radicals.

Examples of halogen-substituted C₁-C₂₀-alkyl radicals are alkyl radicalssubstituted by fluorine, chlorine, bromine and iodine atoms, such as the3,3,3-trifluoro n-propyl radical, the2,2,2,2′,2′,2′-hexafluoroiso-propyl radical and the heptafluoroisopropylradical.

The unsubstituted C₁-C₁₂-alkyl radicals are particularly preferred.

Examples of C₂-C₆-alkoxy radicals are the ethoxy, n-propoxy, isopropoxy,n-butoxy, isobutoxy, sec-butoxy and tert-butoxy radicals; pentyloxyradicals, such as the n-pentyloxy radical, and hexyloxy radicals, suchas the n-hexyloxy radical. The ethoxy radicals are particularlypreferred.

The alkoxy radicals may be substituted by halogen atoms, but this is notpreferred.

The aqueous cream may contain an organopolysiloxane (A2) containingalkoxy groups, or a mixture of several organopolysiloxanes. Theorganopolysiloxanes may additionally contain hydroxyl groups, whichfacilitate binding to the building materials.

The organopolysiloxanes (A2) preferably have a viscosity of not morethan 2000 MPa.s, in order to achieve a particularly good distribution onthe pore surfaces in the masonry. It is also possible to useorganopolysiloxanes having a higher viscosity, including solid resins,e.g. solid methylsilicone resins having a molecular weight of 2000 to10,000 g/mol with, for example, a glass transition temperature range of40-50° C., or solid resins comprising R₃SiO_(0.5) and SiO₂ units (MQresins) having a preferred ratio of R₃SiO_(0.5) to SiO₂ of 0.4:1 to1.2:1. These are preferably present in solution in silanes (A1) or inlow-viscosity organopolysiloxanes (A2) or in the organic solvent (D).

The organopolysiloxanes (A2) comprising units of the general formula (I)$\begin{matrix}{R_{x}{{Si}\left( {OR}^{1} \right)}_{y}{{Si}({OH})}_{z}O_{\frac{4 - x - y - z}{2}}} & (I)\end{matrix}$

in which

R denote identical or different monovalent, optionallyhalogen-substituted C₁-C₂₀-hydrocarbon radicals bonded via SiC,

R¹ denote identical or different monovalent C₁-C₆alkyl radicals,

x denotes 0, 1, 2 or 3, on average 0.8 to 1.8,

y denotes 0, 1, 2 or 3, on average 0.01 to 2.0, and

z denotes 0, 1, 2 or 3, on average 0.0 to 0.5, with the proviso that thesum of x, y and z is not more than 3.5, are particularly suitable.

Examples of the C₁-C₂₀-hydrocarbon radicals are the C₁-C₂₀-alkylradicals and halogen-substituted C₁-C₂₀-alkyl radicals mentioned abovein the case of the organoalkoxysilanes (A1), the alkenyl radicals, suchas the vinyl, allyl, n-5-hexenyl, 4-vinylcyclohexyl and 3-norbornenylradicals; aryl radicals, such as the phenyl, biphenylyl, naphthyl,anthryl and phenanthryl radicals; alkaryl radicals, such as o-, m- andp-tolyl radicals, xylyl radicals and ethylpheyl radicals; aralkylradicals, such as the benzyl radical, the alpha- and the β-phenylethylradical. The unsubstituted C₁-C₁₂-alkyl radicals and the phenyl radicalare particularly preferred.

Although not indicated in the abovementioned formula, some of theradicals R can be replaced by hydrogen atoms bonded directly to siliconatoms. However, this is not preferred.

Examples of the radicals R¹ are the methyl, ethyl, n-propyl, isopropyl,n-butyl, sec-butyl and tert-butyl radicals; pentyl radicals, such as then-pentyl radical, and hexyl radicals, such as the n-hexyl radical, themethyl and ethyl radicals being particularly preferred.

Preferably, x has an average value of 0.9 to 1.2. Preferably, y has avalue of 0.01 to 1.2. Preferably, z has an average value of 0.0 to 0.2.

Examples of organosiloxanes (A2) are those which are obtainable byreacting methyltrichlorosilane and optionally aC₁-C₈-alkyltrichlorosilane and optionally dimethyldichlorosilane orphenyltrichlorosilane with methanol or ethanol in water, such as theorganopolysiloxanes of the empirical formulae

CH₃Si(OC₂H₅)_(0.8)O_(1.1),

C₆H₅Si(OC₂H₅)_(0.72)O_(1.14),

(CH₃)_(0.7)(iso-octyl)_(0.3)(OCH₃)_(0.6)SiO_(1.2),

CH₃(OC₂H₅)_(0.02)SiO_(1.49) or

(CH₃)_(1.2)(OC₂H₅)_(0.02)SiO_(1.39)

The alkoxysilanes (B1) optionally used in addition to component (A) andcontaining aminoalkyl groups are preferably C₁-C6-alkoxysilanes (B1) andhave in particular the general formula (II)

R² _(u)R³ _(v)Si(OR⁴)_(4-u-v)  (II),

in which R², R³ and R⁴ have the meanings mentioned below in the case ofthe general formula (III) and

u is 0, 1 or 2 and

v is 1, 2 or 3,

with the proviso that the sum of u and v is less than or equal to 3.

An example of a preferred alkoxysilane (B1) is H₂N (CH₂)₂NH(CH₂)₃—Si(OCH₃)₃.

The organopolysiloxanes (B2) optionally used in addition to component(A) are preferably those comprising units of the general formula (III)$\begin{matrix}{{R_{a}^{2}{R_{b}^{3}\left( {OR}^{4} \right)}_{c}{Si}\quad O_{\frac{4 - a - b - c}{2}}},} & ({III})\end{matrix}$

in which

R² denotes identical or different monovalent, optionallyhalogen-substituted, SiC-bonded C₁-C₂₀-hydrocarbon radicals free ofbasic nitrogen,

R³ denotes identical or different monovalent, optionallyhalogen-substituted, SiC-bonded C₁-C₃₀-hydrocarbon radicals having basicnitrogen,

R⁴ may be identical or different and denotes a hydrogen atom orC₁-C₆-alkyl radicals,

a denotes 0, 1, 2 or 3,

b denotes 0, 1, 2 or 3, on average at least 0.05, and

c denotes 0, 1, 2 or 3,

with the proviso that the sum of a, b and c is less than or equal to 3and that the amine number of the organopolysiloxane (B2) is at least0.01.

The amine number designates the number of ml of 1 N HCl which arerequired for neutralizing 1 g of organopoly-siloxane (B2). The aminenumber of the organopolysiloxane (B2) is preferably at least 0.1, inparticular at least 0.2, and preferably not more than 8, in particularnot more than 4.

Examples and preferred examples of the radical R² are mentioned above inthe case of radical R. In particular, the methyl and the isooctylradical are preferred.

Preferably, a hydrocarbon radical, in particular a methyl radical, isalso bonded to each silicon atom to which a hydrogen atom is bonded.

Radical R³ is preferably a radical of the general formula (IV)

R⁵ ₂NR⁶—  (IV),

in which

R⁵ may be identical or different and denotes hydrogen or a monovalent,optionally substituted C₁-C₁₀-hydrocarbon radical orC₁-C₁₀-amino-hydrocarbon radical and

R⁶ denotes a divalent C₁-C₁₅-hydrocarbon radical.

Examples of the radical R⁵ are the examples of hydrocarbon radicalsgiven for radical R, and hydrocarbon radicals substituted by aminogroups, such as aminoalkyl radicals, the aminoethyl radical beingparticularly preferred.

Preferably, at least one hydrogen atom is bonded to each nitrogen atomin the radicals of the general formula (IV).

Radical R⁶ is preferably a divalent hydrocarbon radical having 1 to 10carbon atoms, particularly preferably 1 to 4 carbon atoms, in particularthe n-propylene radical.

Examples of radical R⁶ are the methylene, ethylene, propylene, butylene,cyclohexylene, octadecylene, phenylene and butenylene radical.

Preferred examples of radicals R³ are

H₂N(CH₂)₃—,

H₂N(CH₂)₂NH(CH₂)₂—,

H₂N(CH₂)₂NH(CH₂)₃—,

H₂N(CH₂)₂—,

H₃CNH(CH₂)₃—,

C₂H₅NH(CH₂)₃—,

H₃CNH(CH₂)₂—,

C₂H₅NH(CH₂)₂—,

H₂N(CH₂)₄—,

H₂N(CH₂)₅—,

H(NHCH₂CH₂)₃—,

C₄H₉NH(CH₂)₂NH(CH₂)₂—,

cyclo-C₆H₁₁NH(CH₂)₃—,

cyclo-C₆H₁₁NH(CH₂)₂—,

(CH₃)₂N(CH₂)₃—,

(CH₃)₂N(CH₂)₂—,

(C₂H₅)₂N(CH₂)₃— and

(C₂H₅)₂N(CH₂)₂—.

The examples of alkyl radicals R¹ are also fully applicable to theradical R⁶.

Examples and preferred examples of the radical R⁴ are mentioned above inthe case of radical R¹. In particular, the methyl and the ethyl radicalare preferred.

The preferred average value for a is 0 to 2, in particular 0 to 1.8.

The preferred average value for b is 0.1 to 0.6, in particular 0.15 to0.30.

The preferred average value for c is 0 t6 0.8, in particular 0.01 to0.6.

Preferably, the organopolysiloxanes (B2) have a viscosity of 5 to 5000,in particular of 100 to 3000, mPa.s at 25° C.

Organopolysiloxanes (B2) can be prepared in a known manner, for exampleby equilibration or condensation of silanes having amino functionalgroups with organpolysiloxanes which contain alkoxy groups and/orhydroxyl groups and which are free of basic nitrogen.

The aqueous creams contain an emulsifier (C) known per se.

Particularly suitable anionic emulsifiers are:

1. Alkylsulphates, particularly those having a chain length of 8 to 18 Catoms, alkyl- and alkarylether-sulphates having 8 to 18 C atoms in thehydrophobic radical and 1 to 14 ethylene oxide (EO) or propylene oxide(PO) units.

2. Sulphonates, in particular alkylsulphonates having 8 to 18 C atoms,alkylarylsulphonates having 8 to 18 C atoms, taurides, esters andmonoesters of sulphosuccinic acid with monohydric alcohols oralkylphenols having 4 to 15 C atoms; these alcohols or alkylphenols mayalso be optionally ethoxylated with 1 to 40 EO units.

3. Alkali metal and ammonium salts of carboxylic acids having 8 to 20 Catoms in the alkyl, aryl, alkaryl or aralkyl radical.

4. Partial phosphoric acid esters and their alkali metal and ammoniumsalts, in particular alkyl and alkaryl phosphates having 8 to 20 C atomsin the organic radical, alkyl ether phosphates or alkaryl etherphosphates having 8 to 20 C atoms in the alkyl or alkaryl radical and 1to 40 EO units.

Particularly suitable nonionic emulsifiers are:

5. Polyvinyl alcohol which also contains 5 to 50%, preferably 8 to 20%,of vinyl acetate units, having a degree of polymerization of 500 to3000.

6. Alkyl polyglycol ethers, preferably those having 8 to 40 EO units andalkyl radicals of 8 to 20 C atoms.

7. Alkylaryl polyglycol ethers, preferably those having 8 to 40 EO unitsand 8 to 20 C atoms in the alkyl and aryl radicals.

8. Ethylene oxide/propylene oxide (EO/PO) block copolymers, preferablythose having 8 to 40 EO and PO units.

9. Adducts of alkylamines having alkyl radicals of 8 to 22 C atoms withethylene oxide or propylene oxide.

10. Fatty acids having 6 to 24 C atoms.

11. Alkylpolyglycosides of the general formula with the proviso that thesum of u and v is less than or equal to 3. R—O—Z_(o), in which R*denotes a linear or branched, saturated or unsaturated alkyl radicalhaving on average 8 to 24 C atoms and Z_(o) denotes an oligoglycosideradical with on average O=1-10 hexose or pentose units or mixturesthereof.

12. Natural substances and their derivatives, such as lecithin, lanolin,saponins, cellulose; cellulose alkyl ethers and carboxyalkylcelluloseswhose alkyl groups each have up to 4 carbon atoms.

13. Linear organo(poly)siloxanes containing polar groups, in particularthose having alkoxy groups of up to 24 C atoms and/or up to 40 EO and/orPO groups.

Particularly suitable cationic emulsifiers are:

14. Salts of primary, secondary and tertiary fatty amines having 8 to 24C atoms with acetic acid, sulphuric acid, hydrochloric acid orphosphoric acids.

15. Quaternary alkyl- and alkylbenzeneammonium salts, in particularthose whose alkyl groups have 6 to 24 C atoms, in particular thehalides, sulphates, phosphates and acetates.

16. Alkylpyridinium, alkylimidazolinium and alkyl-oxazolinium salts, inparticular those whose alkyl chain has up to 18 C atoms, especially thehalides, sulphates, phosphates and acetates.

Particularly suitable ampholytic emulsifiers are:

17. Amino acids having long-chain substituents, such asN-alkyldi(aminoethyl)glycine or salts of N-alkyl-2-aminopropionic acid.

18. Betaines, such as N-(3-acylamidopropyl)-N,N-dimethylammonium saltshaving a C₈-C₁₈-acyl radical and alkylimidazolium betaines.

Preferred emulsifiers are nonionic emulsifiers, in particular the alkylpolyglycol ethers mentioned above under 6., the adducts of alkylamineswith ethylene oxide or propylene oxide which are mentioned under 9., thealkylpolyglycosides mentioned under 11. and the polyvinyl alcoholmentioned under 5. Particularly preferred polyvinyl alcohols stillcontain 5 to 20%, in particular 10 to 15%, of vinyl acetate units andpreferably have a degree of polymerization of 500 to 3000, in particularof 1200 to 2000.

In order to establish any desired active ingredient content, the aqueouscreams contain, as component (D), a water-immiscible organic solventwhich preferably has a solubility of at most less than 1% by weight inwater at 20° C. and preferably has a boiling point of 60 to 280° C.Suitable organic solvents (D) are, for example, alkanes having boilingpoints preferably in the range from 60 to 280° C., particularlypreferably 90 to 220° C., aromatic hydrocarbons, such as toluene,xylenes, trimethylbenzenes and tetramethylbenzenes, chloro-hydrocarbons,such as trichloroethylene or 1,1,1-trichloropropane, ketones, esters,such as n- or tert-butyl acetate, relatively long-chain alcohols, suchas hexanols, heptanols or octanols, and relatively long-chain ethers,such as di-n-octyl ether. Owing to their low odour, alkanes,dearomatized or petroleum hydrocarbons and isoparaffins having boilingpoints in the range from 100 to 220° C. are particularly preferred.

The water-repellent creams described in EP-A-819 665 also have thedisadvantage that, particularly in the case of very absorptive buildingmaterials of low alkalinity, such as, for example, clay bricks, poorwater-repellency is produced directly at the surface of the buildingmaterial.

The aqueous creams according to the invention may contain, as anadditive, finely divided silicas (E) which have been renderedwater-repellent and which further improve the water-repellency of thesurfaces, also of absorptive surfaces of low alkalinity. In fact, thesilicas (E) accumulate at the surface of the building material. In thisway, considerable water-repellency is obtained very rapidly afterimpregnation. Suitable silicas (E) are obtainable, for example, ifsilica obtained by flame hydrolysis or precipitation is renderedwater-repellent with organosilicon compounds, in particular silanes. Thesilicas (E) preferably have a specific surface area of at least 40 m²/g,particularly preferably at least 60 m²/g.

Hydrophobic solids cannot be emulsified in the water-repellent creamsdisclosed in EP-A-819 665, since the creamy consistency is destroyed asa result.

The total amount of the active ingredient components (A) and (B) in theaqueous creams is preferably 1 to 80% by weight, in particular 2 to 70%by weight.

The amount of the component (B) in the aqueous creams is preferably 0.1to 20% by weight, in particular 0.2 to 10% by weight.

The amount of the emulsifier (C) in the aqueous creams is preferably 0.1to 10% by weight, in particular 0.2 to 5% by weight.

The content of organic solvent (D) in the aqueous cream is preferably 1to 95% by weight, in particular 5 to 80% by weight.

The content of silicas (E) in the aqueous creams is preferably 0.01 to4% by weight, in particular 0.01 to 2% by weight.

The aqueous creams may also contain buffer substances which stabilizethe pH in the range from 5 to 8, in which the alkyltrialkoxysilanes arevery resistant to hydrolysis. All organic and inorganic acids and baseswhich are chemically inert to the other components of the emulsions, inparticular the alkali metal, alkaline earth metal and ammonium salts ofcarboxylic acids, phosphoric acid, carbonic acid and sulphuric acid, aresuitable. Sodium carbonate, sodium bicarbonate, sodium hydrogenphosphate and a mixture of acetic acid and aqueous ammonia solution areparticularly preferred. The amount of buffer substances is preferablynot more than 3, in particular 1, % by weight of the total amount of thecreams.

The aqueous creams may also contain additives for improving thewater-repellency, for example metal soaps, such as stearates or oleates.

In addition to the components described above, the aqueous creams maycontain fungicides, bactericides, algicides, microbicides, odoursubstances, corrosion inhibitors and antifoams as additives. Thepreferred amount of additives is not more than 2, in particular 0.5, %by weight of the total amount of the creams.

The aqueous creams are prepared by conventional methods for thepreparation of aqueous creams.

For this purpose, one possibility is initially to prepare a cream fromthe components (A), (B) and (C) by a process described in EP-A-819 665.Organic solvent (D) is then stirred into said cream in an amountsufficient to give the desired active ingredient content.

In a further preferred process, the components (A), (B) and (D) arepremixed and are slowly emulsified in the aqueous solution of theemulsifier (C) until a creamy consistency is achieved.

Also preferred is a process in which the components (A) and (B) arepremixed with only some of the total amount of the component (C) andemulsified in the water-emulsifier mixture until a creamy consistency isobtained. Finally, the amount of solvent (D) still remaining is thenstirred into the creamy emulsion.

If solid resins comprising R₃SiO_(0.5) and SiO₂ units are used, theseare dissolved in the silanes (A1) or in the solvent (D) beforepreparation of the cream according to the invention.

The preparation of the aqueous creams according to the invention ispreferably carried out in pressure emulsifiers, colloid mills or inparticular in a high-speed stator-rotor stirring apparatus according toProf. P. Willems. If a further solvent (D) is added to a cream which hasalready been prepared, said solvent is preferably stirred in withoutextreme application of shear force, in order to avoid destroying thestiff emulsion phase producing the creamy consistency.

The aqueous creams are particularly suitable for the water-repellentimpregnation and priming of mineral building materials, such as naturalor artificial stone, concrete and reinforced concrete, cellularconcrete, sand-lime bricks, clay bricks, clinker, marble or granite.

The aqueous creams are particularly suitable for impartingwater-repellency to mineral-bound, preferably cement-bound, fibrebuilding materials whose fibres consist of natural fibres or manmadefibres. Suitable natural fibres are mineral fibres, such as rock wool,quartz fibres or ceramic fibres, or vegetable fibres, such as cellulose.Suitable manmade fibres are, for example, glass fibres, plastics fibresand carbon fibres. The use of the aqueous cream for impartingwater-repellency to cement-bound cellulose fibre components isparticularly preferred. The cellulose fibres may be, for example, jute,coconut or hemp fibres or may originate from paper, cardboard or wastepaper.

The aqueous creams are preferably applied to the building material byspraying, brushing, rolling or trowelling. The coat thickness ispreferably 0.05 to 3 mm, particularly preferably 0.1 to 2 mm.

In the following examples, all stated parts and percentages relate toweight, unless stated otherwise. Unless stated otherwise, the followingexamples are carried out at a pressure of the ambient atmosphere, i.e.at about 0.10 MPa, and at room temperature, i.e. at about 20° C., or ata temperature which is established on combining the reactants at roomtemperature without additional heating or cooling. The active ingredientcontent of the aqueous creams is defined as the sum of all organosiliconcomponents.

EXAMPLES

The Following are used as Component (A):

H1: Isooctyltriethoxysilane

H2: Organopolysiloxane of the empirical formulaCH₃Si(OC₂H₅)_(0.8)O_(1.1) having an average molecular weight of about650 g/mol and a viscosity of about 20 mm²/s.

H3: Methylsilicone resin present as a highly viscous liquid andcomprising CH₃SiO_(3/2) units, with about 20 mol % of (CH₃)SiO_(2/2)units and about 5 mol % of C₂H₅O/SiO_(3/2) units and a molecular weightof about 5000 g/mol.

The Following are Optionally used as Component (B):

N1: Condensate of an α,ω)-dihydroxymethylpolysiloxane having anSi-bonded hydroxyl group in each of the terminal units andN-(2-aminoethyl)-3-aminopropyltrimethoxysilane in the presence of KOH,having an amine number of about 0.3, a viscosity of about 1500 mm²/s at25° C. and a residual methoxy content of less than 5 mol %, based on themethoxy groups initially present in theN-(2-aminoethyl)-3-aminopropyltrimethoxysilane.

N2: N-(2-Aminoethyl)-3-aminopropyltrimethoxysilane

The Following are used as Component (C):

E1: Reaction product of stearylamine and ethylene oxide, having analkali number of 48 to 51 mg KOH/g.

E2: Isotridecyl alcohol glycol ether having 10 ethylene oxide units, 80%strength in water.

The Following are used as Component (D):

LM1: Mineral spirit crystal oil K30 (Deutsche Shell Chemie GmbH)

LM2: Isoparaffin ISOPAR® H (Deutsche Exxon Chemical GmbH)

Example 1

1.6 g each of emulsifier E1 and E2 are mixed with 30.4 g of water, and34 g of component N1 are then incorporated by emulsification in ahigh-speed stator/rotor stirring apparatus. 306 g of silane H1 and 26.4g of water are then incorporated, alternately in 6 portions, in ahigh-speed stator/rotor stirring apparatus into the emulsion thusobtained, until a white, aqueous cream is obtained. This cream is thendivided into two equal portions. 140 g of mineral spirit LM1 are stirredinto one portion without significant introduction of shear forces(→Cream 1: 50% of active ingredient), and 650 g of LM1 are stirred intothe other portion (→Cream 2: 20% of active ingredient).

Example 2

2 g of emulsifier E2 are mixed with 79.5 g of water, 2 g of component N2and 0.5 g of acetic acid. 300 g of isoparaffin LM2 are then emulsifiedin this mixture in a high-speed stator/rotor stirring apparatus, theemulsion thus obtained already having considerable thickness. 384 g of aprepared mixture of 67 parts by weight of silane H1, 7 parts by weightof organopolysiloxane H2 and 26 parts by weight of silicone resin H3 arethen emulsified in portions in this already stiff phase (→Cream 3: 50%of active ingredient).

Example 3

Example 2 is repeated, except that 600 g of isoparaffin LM2 and only 77g of the active ingredient mixture comprising 67 parts by weight ofsilane Hi, 7 parts by weight of organopolysiloxane H2 and 26 parts byweight of silicone resin H3 are used (→Cream 4: 10% active ingredientcontent).

Silicone Pastes and Cream for Comparative Experiments

Paste 1: 340 g of silane H1 are diluted with 280 g of solvent LM1 andthen mixed with 48 g of bentonite (Bentone® 34) and 12 g of ethanol withthe aid of a low-speed stirrer until a relatively highly viscous,ochre-coloured paste results (→Paste 1: 50% active ingredient content).

Paste 2: 80 g of the prepared active ingredient mixture from Example 2,consisting of 67 parts by weight of silane H1, 7 parts by weight oforganopolysiloxane H2 and 26 parts by weight of silicone resin H3, arediluted with 680 g of solvent LM2. 40 g of a hydrophobic pyrogenicsilica (surface occupied by trimethylsiloxy group; specific surfacearea: 130 g/m²) are then stirred into this solution, a pasty consistencybeing obtained (→Paste 2: 10% active ingredient content).

Cream 5: 1.6 g each of emulsifier E1 and E2 are mixed with 57 g ofwater, and 34 g of component N1 are then incorporated by emulsificationin a high-speed stator/rotor stirring apparatus. 306 g of silane H1 and26.4 g of water are then incorporated, alternately in 6 portions, in ahigh-speed stator/rotor stirring apparatus into the emulsion thusobtained, until a white, aqueous cream is obtained (→Cream 5: 80% activeingredient content, solvent-free).

Example 4 (Shelf-Life of the Creams According to the Invention)

None of the creams according to the invention from Examples 1-3 showsany optical change either after storage for 14 days at 50° C. or after 6months at room temperature. They thus have a long shelf life. In thecase of the comparative products Paste 1 and Paste 2, on the other hand,there is a substantial separation of clear liquid both at 50° C. and atroom temperature.

Example 5 (Imparting Water-Repellency to Lime-Sand Brick)

Creams 1 to 4 according to the invention and Pastes 1 and 2 notaccording to the invention are applied with a brush to sand-lime slabs(about 10×10×2.5 cm³). The amount applied is about 300 g/m². Afterstorage for 14 days at room temperature, the surface of the testspecimen is visually assessed, after which the specimens and untreatedreference test specimens are placed in water (submerged in water to adepth of 5 cm) and their water absorption is determined as relativeweight increase after 24 hours. The test specimens are then dried andbroken, and the thickness of the hydrophobic zone (equal to the depth ofpenetration of the water-repellent active ingredients) is determined bydripping water on the fracture surface. By measuring the contact angleof water dripped on, the water-repellency is assessed. Contact anglesof >90° denote good water-repellency, and those of <90° indicate wettingand thus represent fairly poor water-repellency. The results of thesetests are summarized in Table I.

TABLE I Depth Water of Water- absorp- penetra- repel- Contact SurfaceProduct tion tion lency angle change Cream 1 0.9% >10 mm Good 110° NoneCream 2 1.0% 6-8 mm Good 115° None Cream 3 0.7% >10 mm Very 130° Nonegood Cream 4 0.8% 5-7 mm Very 135° None good Paste 1 1.2% >10 mm Poor 30° Brown, loam- like Paste 2 1.0% 3-6 mm Very 135° White good coatingUntreated 12.3% — — — —

As is evident from Table I, all products lead to a dramatic reduction inthe capillary water absorption. With the exception of paste 1, goodwater-repellency is also achieved throughout. While the creams accordingto the invention do not change the appearance of the slabs, thecomparative pastes Paste 1 and Paste 2 result in substantial changes.

Example 6 (Imparting Water-Repellency to Clay Bricks)

Creams 1 to 4 according to the invention and Pastes 1 and 2 prepared forcomparative purposes and Cream 5 are applied to clay brick (about22×10×7 cm³) by means of a brush in an amount of about 500 g/m². After adrying time of 14 days, water absorption, water-repellency and contactangle, depth of penetration and surface change are determinedanalogously to Example 5. The results of these tests are summarized inTable II.

TABLE II Depth Water of Water- absorp- penetra- repel- Contact SurfaceProduct tion tion lency angle change Cream 1 0.5% >50 mm Good 110° NoneCream 2 0.7% 22-28 mm Good 115° None Cream 3 0.3% >50 mm Very 125°Slight good deep- ening of colour Cream 4 0.6% 17-23 mm Very 135° Nonegood Paste 1 7.5% >50 mm None <10° Dark, loam- like Paste 2 2.3% 15-20mm Good 110° White coating Cream 5 0.9% >50 mm Poor <30° None Untreated17.6% — — — —

The creams according to the invention all have an outstandingwater-repellent effect and, with the exception of Cream 3, furthermoredo not lead to any deepening of colour. The slight deepening of colourwith Cream 3 is due to the high active ingredient content of this creamin combination with a high polysiloxane content.

Comparative pastes 1 and 2 change the appearance of the bricksconsiderably. Since they are free of water, the reaction to give thehydrophobic, polymeric active ingredient on the nonalkaline bricks takesa very long time, resulting in the evaporation of considerable amountsof the volatile active components. In the case of the silane-richproduct Paste 1, there is therefore no water-repellent effect at all onthe surface, and the water absorption too is unacceptably high. In thecase of Paste 2, slightly better results are obtained owing to thepolysiloxane content.

In the case of Cream S which contains 80% of active ingredient and issolvent-free and therefore not according to the invention, theaccumulation of emulsifier and depletion of active ingredient result, onthe surface, in hydrophobic characteristics which are poor on thesurface and which manifest themselves in particular in an unacceptablypoor water-repellency.

Example 7 (Imparting Water-Repellency to Concrete)

Creams 1 and 3 according to the invention are sprayed by the airlessmethod, in an amount of about 200 g/m², onto concrete slabs (30×30×6cm³) of concrete quality class B 45 (compressive strength 45 N/mm²),said slabs being set up perpendicularly. The creams form a white film onthe concrete surface, which film disappears completely within about 2hours. For comparison, two further concrete slabs were sprayed withlow-viscosity impregnating compositions, that is to say one with anaqueous emulsion (abbreviation EM50) containing 50% of active ingredient(n-octyltriethoxysilane) and the other with a solution (abbreviationSO50) likewise containing 50% of active ingredient (1 part by weight ofa polysiloxane of the (abbreviation SO50) likewise containing 50% ofactive ingredient (1 part by weight of a polysiloxane of the averageformula CH₃Si(OC₂H₅)_(0.80)O_(1.1), having a viscosity of 20 mm²/s, 4parts by weight of isooctyl-triethoxysilane). With dense spraying-on, amaximum product absorption of about 65 g/m² is achieved with the aqueousproduct EM50 and then absorption of about 80 g/m² with thesolvent-containing product SO50. Higher application rates are notpossible in one operation.

After impregnation, all test specimens were stored for 14 days at roomtemperature, after which the water absorption was determined withstorage for 7 days in water (water level 5 cm above the test specimens).The test specimens were then broken, and the depth of penetration of theactive ingredient was measured by dripping on water. Table III shows theresults.

TABLE III Water Depth of Surface Product absorption penetration changeCream 1 0.08% 5-7 mm None Cream 3 0.13% 3-5 mm Slight deepening ofcolour EM50 0.67% 0.5-1 mm None SO50 0.46% 1-2 mm Slight deepening ofcolour Untreated 1.21% — —

As is evident from Table III, the two Creams 1 and 3 reduce the waterabsorption of the concrete substantially better than the low-viscosityproducts, owing to higher application rates and greater depth ofpenetration. The polysiloxane content of Cream 3 and SO50 leads to aslight deepening of colour on the dense concrete.

Example 8 (Priming of Concrete)

In each case 250 g/m² of Cream 1, and, for comparison, the same amountof Paste 1 were applied by means of a brush to mortar samples which hadbeen produced according to DIN EN 196 T1 (water/cement ratio 0.5) andstored for at least 90 days under standard temperature and humidityconditions (DIN 50014; 23° C./50% relative humidity). After storage for7 days at room temperature, the test specimens treated in this mannerand untreated reference samples were brushed off with a coarse scrubbingbrush and coated with an emulsion paint based on acrylic resin (StoCryl®V100, Sto AG, D-79780 Stühlingen). After drying, the adhesive strengthof the paint was determined according to ISO 4624. Thereafter, the testspecimens were broken and the depth of penetration of the hydrophobicactive ingredient was determined by dripping on (Table IV).

TABLE IV Adhesive Depth of Product strength penetration Cream 1 −2.7N/mm² 8-10 mm Paste 1 0.6 N/mm² 7-10 mm Untreated 2.4 N/mm² —

As is evident from Table IV, the paint adhesion to the test specimensprimed with Cream 1 is even higher than to the unimpregnated ones. Inthe case of priming with Paste 1, on the other hand, in spite ofbrushing off, water-repellent bentonite remains on the sample surface inan amount such that the paint adhesion is dramatically reduced. Paste 1is consequently completely unsuitable for priming to impartwater-repellency.

Example 9 (Cream Containing Solid)

2 g of emulsifier E2 are mixed with 79.5 g of water, 2 g of component N2and 0.5 g of acetic acid, analogously to the preparation of Cream 4 inExample 3. 600 g of isoparaffin LM2 are then emulsified in this mixturein a high-speed stator/rotor stirring apparatus, the emulsion thusobtained already being considerably thickened. 77 g of a preparedmixture of 67 parts by weight of silane H1, 26 parts by weight ofsilicone resin H3 and 7 parts by weight of a silica-modifiedorganopolysiloxane are then emulsified in portions in this already stiffphase. For the preparation of the silica-modified organopolysiloxane,200 g of a finely divided hydrophobic silica (specific surface area ofabout 140 m²/g) are stirred uniformly into 800 g of organopolysiloxaneH2 (→Cream 6: 10% of active ingredient, including silica).

Comparative Example (Solvent-Free Cream Containing Solid)

2 g of emulsifier E2 are mixed with 79.5 g of water, 2 g of component N2and 0.5 g of acetic acid. 414 g of a prepared mixture of 67 parts byweight of silane H1, 26 parts by weight of silicone resin H3 and 7 partsby weight of a silica-modified organopolysiloxane are then emulsified inportions in this mixture in a high-speed stator/rotor stirringapparatus. For the preparation of the silica-modifiedorganopolysiloxane, 200 g of a finely divided hydrophobic silica(specific surface area about 140 m²/g) are stirred uniformly into 800 gof organopolysiloxane.

Surprisingly, only a low-viscosity emulsion is obtained instead of acream.

For comparison, the experiment is repeated, except that the originalorganopolysiloxane H2 is used instead of the silica-modifiedorganopolysiloxane. In this experiment, a creamy consistency is obtainedwithout problems.

Solvent-free creams are consequently not obtainable or not stable in thepresence of finely divided hydrophobic silica.

Example 10 (Early Water Resistance)

Creams 4 and 6 according to the invention and the solvent-freecomparative cream 5 are applied to clay bricks (about 22×10×7 cm³) bymeans of a brush in an amount of about 500 g/m². After 4 hours and aftera drying time of 1 day at room temperature, water is dripped onto thebricks thus treated, and the wetting behaviour and the appearance of thesurface are assessed qualitatively (Table V).

TABLE V Wetting behaviour Surface Product after 4 h after 24 h changeCream 4 Wet to a great Wet slightly None extent Cream 5 Wet completelyWet completely None Cream 6 Good water- Very good water- None repellencyrepellency

The results confirm that the hydrophobic silica of Cream 6 accumulateson the surface of the building material and produces pronouncedwater-repellency there immediately after penetration of the cream film.In the case of Creams 4 and 5, on the other hand, it is necessary forthe silane or siloxane components H1, H2 and H3 to form a silicone resinnetwork by reaction with moisture in order to give rise towater-repellency. This reaction takes substantially longer than 24 hourson the nonalkaline clay brick.

What is claimed is:
 1. An aqueous, firm cream, comprising: A) one ormore organosilicon compounds selected from A1) C₁₋₂₀-alkyl-C₂₋₆alkoxysilanes, and A2) alkoxy-functional organopolysiloxanes; B)optionally, one or more organosilicon compound containing aminoalkylgroups, selected from B1) aminoalkyl group-containing alkoxysilanes, B2)Si—C bonded, aminoalkyl group-containing organopolysiloxanes having anamine number of at least 0.01; C) one or more emulsifiers; D) one ormore organic solvents immiscible with water, in an amount of 1 to about95% by weight based on the total weight of the aqueous, firm cream; andE) optionally a finely divided, water-repellant silica, wherein theamount of components A) and B) totals from 1 to 80 weight percent basedon the total weight of the cream.
 2. The cream of claim 1, wherein thesum of components A) and B) is from 5 to 50 weight percent based on thetotal weight of the cream.
 3. The cream of claim 1, wherein said organicsolvent is present in an amount of 5 to 80% by weight based on the totalweight of the cream.
 4. The cream of claim 2, wherein said organicsolvent is present in an amount of 5 to 80% by weight based on the totalweight of the cream.
 5. The cream of claim 1, wherein said waterrepellant silica is a hydrophobicized silica having a BET surface areaof 40 m²/g or more, present in an amount of 0.01 to 4 weight percentbased on the total weight of the cream.
 6. The cream of claim 1, whereinthe C₁₋₂₀-alkyl-C₂₋₆-alkoxysilanes (A1) have one or two identical ordifferent, optionally halogen-substituted, monovalent C₁₋₂₀-alkylradicals bonded via SiC, and the remaining radicals are identical ordifferent C₂₋₆-alkoxy radicals.
 7. The cream of claim 2, wherein theC₁₋₂₀-alkyl-C₂₋₆-alkoxysilanes (A1) have one or two identical ordifferent, optionally halogen-substituted, monovalent C₁₋₂₀-alkylradicals bonded via SiC, and the remaining radicals are identical ordifferent C₂₋₆-alkoxy radicals.
 8. The cream of claim 3, wherein theC₁₋₂₀-alkyl-C₂₋₆-alkoxysilanes (A1) have one or two identical ordifferent, optionally halogen-substituted, monovalent C₁₋₂₀-alkylradicals bonded via SiC, and the remaining radicals are identical ordifferent C₂₋₆-alkoxy radicals.
 9. The cream of claim 1, in which theorganopolysiloxanes (A2) comprise units of the general formula (I)$\begin{matrix}{R_{x}{{Si}\left( {OR}^{1} \right)}_{y}{{Si}({OH})}_{z}O_{\frac{4 - x - y - z}{2}}} & (I)\end{matrix}$

in which R are identical or different monovalent, optionallyhalogen-substituted C₁₋₂₀-hydrocarbon radicals bonded via SiC, R¹ areidentical or different monovalent C₁₋₆-alkyl radicals, x is 0, 1, 2 or3, on average 0.8 to 1.8, y is 0, 1, 2 or 3, on average 0.01 to 2.0, andz is 0, 1, 2 or 3, on average 0.0 to 0.5, with the proviso that the sumof x, y and z is not more than 3.5.
 10. The cream of claim 2, in whichthe organopolysiloxanes (A2) consist of units of the general formula (I)$\begin{matrix}{R_{x}{{Si}\left( {OR}^{1} \right)}_{y}{{Si}({OH})}_{z}O_{\frac{4 - x - y - z}{2}}} & (I)\end{matrix}$

in which R are identical or different monovalent, optionallyhalogen-substituted C₁₋₂₀-hydrocarbon radicals bonded via SiC, R¹ areidentical or different monovalent C₁₋₆-alkyl radicals, x is 0, 1, 2 or3, on average 0.8 to 1.8, y is 0, 1, 2 or 3, on average 0.01 to 2.0, andz is 0, 1, 2 or 3, on average 0.0 to 0.5, with the proviso that the sumof x, y and z is not more than 3.5.
 11. The cream of claim 3, in whichthe organopolysiloxanes (A2) consist of units of the general formula (I)$\begin{matrix}{R_{x}{{Si}\left( {OR}^{1} \right)}_{y}{{Si}({OH})}_{z}O_{\frac{4 - x - y - z}{2}}} & (I)\end{matrix}$

in which R are identical or different monovalent, optionallyhalogen-substituted C₁₋₂₀-hydrocarbon radicals bonded via SiC, R¹ areidentical or different monovalent C₁₋₆-alkyl radicals, x is 0, 1, 2 or3, on average 0.8 to 1.8, y is 0, 1, 2 or 3, on average 0.01 to 2.0, andz is 0, 1, 2 or 3, on average 0.0 to 0.5, with the proviso that the sumof x, y and z is not more than 3.5.
 12. The cream of claim 1, in whichthe organopolysiloxanes (B1) are present and comprise units of thegeneral formula (III) $\begin{matrix}{R_{a}^{2}{R_{b}^{3}\left( {OR}^{4} \right)}_{c}{Si}\quad O_{\frac{4 - a - b - c}{2}}} & ({III})\end{matrix}$

in which R² are identical or different monovalent, optionallyhalogen-substituted, SiC-bonded C₁₋₂₀hydrocarbon radicals free of basicnitrogen, R³ are identical or different monovalent, optionallyhalogen-substituted SiC-bonded C₁₋₃₀hydrocarbon radicals having basicnitrogen, R⁴ are identical or different and are a hydrogen atom orC₁₋₆-alkyl radicals, a is 0, 1, 2 or 3, b is 0, 1, 2 or 3, on average atleast 0.05, and c is 0, 1, 2 or 3, with the proviso that the sum of a, band c is less than or equal to 3 and that the amine number of theorganopolysiloxane (B2) is at least 0.01.
 13. The cream of claim 2, inwhich the organopolysiloxanes (B1) are present and comprise units of thegeneral formula (III) $\begin{matrix}{R_{a}^{2}{R_{b}^{3}\left( {OR}^{4} \right)}_{c}{Si}\quad O_{\frac{4 - a - b - c}{2}}} & ({III})\end{matrix}$

in which R² are identical or different monovalent, optionallyhalogen-substituted, SiC-bonded C₁₋₂₀-hydrocarbon radicals free of basicnitrogen, R³ are identical or different monovalent, optionallyhalogen-substituted SiC-bonded C₁₋₃₀ -hydrocarbon radicals having basicnitrogen, R⁴ are identical or different and are a hydrogen atom orC₁₋₆-alkyl radicals, a is 0, 1, 2 or 3, b is 0, 1, 2 or 3, on average atleast 0.05, and c is 0, 1, 2 or 3, with the proviso that the sum of a, band c is less than or equal to 3 and that the amine number of theorganopolysiloxane (B2) is at least 0.01.
 14. The cream of claim 2, inwhich the organopolysiloxanes (B1) are present and comprise units of thegeneral formula (III) $\begin{matrix}{R_{a}^{2}{R_{b}^{3}\left( {OR}^{4} \right)}_{c}{Si}\quad O_{\frac{4 - a - b - c}{2}}} & ({III})\end{matrix}$

in which R² are identical or different monovalent, optionallyhalogen-substituted, SiC-bonded C₁₋₂₀-hydrocarbon radicals free of basicnitrogen, R³ are identical or different monovalent, optionallyhalogen-substituted SiC-bonded C₁₋₃₀-hydrocarbon radicals having basicnitrogen, R⁴ are identical or different and are a hydrogen atom orC₁₋₆-alkyl radicals, a is 0, 1, 2 or 3, b is 0, 1, 2 or 3, on average atleast 0.05, and c is 0, 1, 2 or 3, with the proviso that the sum of a, band c is less than or equal to 3 and that the amine number of theorganopolysiloxane (B2) is at least 0.01.
 15. The cream of claim 1, inwhich the alkoxysilanes (B1) containing aminoalkyl groups have thegeneral formula (II) R² _(u)R³ _(v)Si(OR⁴)_(4-u-v)  (II) in which R² areidentical or different monovalent, optionally halogen-substituted,SiC-bonded C₁₋₂₀-hydrocarbon radicals free of basic nitrogen, R³ areidentical or different monovalent, optionally halogen-substitutedSiC-bonded C₁₋₃₀-hydrocarbon radicals having basic nitrogen, R⁴ areidentical or different and are a hydrogen atom or C₁₋₆-alkyl radicals, uis 0, 1 or 2, and v is 1, 2 or 3, with the proviso that the sum of u andv is less than or equal to
 3. 16. The cream of claim 2, in which thealkoxysilanes (B1) containing aminoalkyl groups have the general formula(II) R² _(u)R³ _(v)Si(OR⁴)_(4-u-v)  (II) in which R² are identical ordifferent monovalent, optionally halogen-substituted, SiC-bondedC₁₋₂₀-hydrocarbon radicals free of basic nitrogen, R³ are identical ordifferent monovalent, optionally halogen-substituted SiC-bondedC₁₋₃₀hydrocarbon radicals having basic nitrogen, R⁴ are identical ordifferent and are a hydrogen atom or C₁₋₆-alkyl radicals, u is 0, 1 or2, and v is 1, 2 or 3, with the proviso that the sum of u and v is lessthan or equal to
 3. 17. The cream of claim 3, in which the alkoxysilanes(B1) containing aminoalkyl groups have the general formula (II) R²_(u)R³ _(v)Si(OR⁴)_(4-u-v)  (II) in which R² are identical or differentmonovalent, optionally halogen-substituted, SiC-bonded C₁₋₂₀-hydrocarbonradicals free of basic nitrogen, R³ are identical or differentmonovalent, optionally halogen-substituted SiC-bonded C₁₋₃₀-hydrocarbonradicals having basic nitrogen, R⁴ are identical or different and are ahydrogen atom or C₁₋₆-alkyl radicals, u is 0, 1 or 2, and v is 1, 2 or3, with the proviso that the sum of u and v is less than or equal to 3.18. The cream of claim 1, wherein the emulsifier comprises one or moreof alkyl polyglycol ethers, polyoxyalkylated alkylamines,alkylpolyglycosides, or polyvinyl alcohols.
 19. The cream of claim 1,wherein said organic solvent comprises one or more of alkane solvents,petroleum hydrocarbons, isoparaffins, long chain alcohols, and ethers.20. A process for impregnating or priming mineral building materials toimpart water-repellency, comprising applying to the building materialthe aqueous cream of claim 1.